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A gram positive, spore forming, obligate anaerobic bacilli has 4 subtypes. What are their mechanisms of action.
- 1. C. tetani- tetanospasmin blocks glycine and GABA from Renshaw cells in the spinal cord.
2. C. botulinum- preformed heat labile toxin that inhibits release of Ach at neurotransmitters.
3. C. perfringens - alpha toxin(lectihinase) that causes myonecrosis and hemolysis
4. C. difficile- Toxin A(enterotoxin) binds brush border and toxin B(cytotoxin) destroys cytoskeletal structure of enterocytes -> pseudomembranous colitis.
What is the difference between primary and secondary tuberculosis caused by mycobacterium tuberculosis?
- occurs in nonimmune host like a child
- forms Ghon complex at base of the lung
- SECONDARY (reactivation):
- occurs in partially immune hypersensitized host like an adult.
- Forms fibrocaseous cavity lesions in upper lobe usually
What bacterias are rods that form white colonies on MacConkay and are oxidase(-)?
- These are lactose nonfermentors gram negative rods:
What is the difference between the subtypes of the gram-negative cocci that ferments glucose and produces IgA protesases?
- 1. Gonococci:
- No polysaccharide capsule
- No maltose fermentation
- no vaccine
- Sexually transmitted
- -> gonorrhea, septic arthritis, neonatal conjunctivitis, PID and Fitz-Hugh-Curtis syndrome.
- 2. Meningococci:
- Via respiratory and oral secretions
- -> meningococcemia and meningitis, Waterhouse-Friderichsen sydrome.
What is the similarity between the bacteria that produces shiga-like toxin and Hemolytic-uremic syndrome and the bacteria that causes lobar pneumonia in alocholics and diabetics?
- EHEC and Klebsiella
- Both are gram negative rods that ferment lacotse on MacConkay fast.
What gram negative rod produces weil's disease.
Leptospira interogans (found in water contaminated with rodent urine)
Weil's = severe form with jaundice and azotemia from liver and kidney dysfunction; fever, hemorrhage and anemia.
What causes the following and how do you treat it?
Stage 1: erythema chronicum migrans(bull's sys red rash) and flulike symptoms.
Stage 2: Bells palsy and AV nodal block
Stage 3: Chronic monoarthritis and migratory polyarthritis, also
Lyme Disease: Borrelia burgdorferi transmitted by Ixodes tick.
Treatment = Doxycycline(early) and ceftriaxone (late)
What is the organism that can cause bacillary angiomatosis in immunocompromised patient's?
Bartonella = cat scratch fever
What disease is caused by the organism that is negative for producing antibodies that cross react to Proteus O antigens and agglutinates?
- This reaction is the Weil-Felix reaction of Rickettsial infections.
- Coxciella burnetti is the rickettsial that tests negative.
- C. burnetti leads to Q fever. (No rash no vector)
What is special about the bacteria that causes atypical pneumonia, is grown on Eaton's agar, and produces high titer of cold agglutinins; which can agglutinate or lyse RBC's?
- This is mycoplasma pneumoniae
- No cell wall
- cholesterol containing membrane
TX: tetracycline or erythromycin
What is important about the dimorphicity of the fungi that causes pneumonia and meningitis: and disseminates to bone and skin. It is found in California.
This is coccidioidomycosis which is a spherule in tissue.
What organism is this?
mold with irregular nonseptate hyphae branching at wide angles. Proliferates in blood vessels , penetrate cribiform plate, -> frontal lobe abscesses, headache, facial pain, and black necrotic eschar on face.
Mucor and Rhizopus spp.
What is the treatment for the dimorphic fungi that lives on vegetation and causes ascending lymphangitis?
- This is sporothrichosis.
- Treatment = itraconazole or potassium iodide.
An neonate presents with chorioretinitis, hydrocephalus, and intracranial calcifications. What should the mother have been treated with.
- This is toxoplasmosis- the cat crap disease
- Treatment: sulfadiazine & pyrimethamine
What is the treatment for the protozoa that causes hemolytic anemia and fever? It is transmitted by Ixodes tick
DX: blood smear- no RBC pigment and appear as Maltese cross.
- This is Babesia
- TX: Quinine, clindamycin
Helminth that contamintes eggs -> granulomas (retinal blindness) and visceral larva migrans. TX: Diethylcarbamazine
Undercooked fish -> causes inflammation of the biliary tract -> pigmented gallstones. Also associated with cholangicarcinoma.
What other Trematodes are treated with the same drug?
This is Clonorchis sinensis and it is treated with Praiquantel.
- Other trematodes are Schistosoma
- and Paragonimus westermani
What are the live attenuated vaccines and which one can be given to HIV(+) patients?
Smallpox, yellow fever, chickenpox(VZV), Sabin's polio virus(orally), and MMR
MMR is the only live attenuated vaccine that can be given to HIV patients
No booster needed.
Organism is transmitted by parental, sexual, and maternal-fetal routes. Predisposes individual to chronic hepatitis, cirrhosis, or hepatocellular carcinoma. What is this organism?
HBV or DNA hepadnavirus (enveloped dsDNA partial circular virus)
A patient's serum contains the following:
What is this patient's status?
This patient has an HBV infection but is now in recovery.
Mutation to what receptor makes a person immune to HIV infection?
What infections is a patient with HIV at risk for with a CD4 count of <200?
Reactivation of HSV, cryptosporidiosis, Isospora, disseminated coccidioidomycosis, and pneumocystis pnemuonia.
What is the normal flora dominant in the oropharnyx?
viridans group streptococci
What are the most common causes of pneumonia in children from 4wks -18 yoa?
- Chlamydia pneumoniae
- Strep pneumo